My current work focuses its investigation on the interaction between group and individual learning. My piece in the Journal of Learning Sciences (Murata, 2013) and the chapter in the upcoming SAGE Handbook of Learning (Murata, in press) conceptualize this interactive relationship by illustrating how the instructional “width” may frame different student learning experiences and outcomes. When instruction is “wide,” different student ideas are incorporated and drive classroom practices, with plenty of intellectual space for students to make connections among their ideas and mathematically-valued ideas (e.g. defined by standards, textbooks). In contrast, when instruction is “narrow,” teachers focus student attention on the right ways of doing mathematics, which can distance some students, especially those from underrepresented communities. The empirical piece I co-wrote with graduate students (Murata, Siker, Kang, Boldinger, Kim, Scott, & Lenouette, under review) illustrates this interactive relationship through a case study of two first-grade teachers during math talk lessons. The study found that when the teacher allowed different student ideas in math talk (wide instruction), even though classroom discussions could sometimes stray and were challenging for the teacher to facilitate, more students came to use the mathematically-valued methods over time, in contrast to when the teacher controlled student discussion more tightly (narrow instruction). The study has an important implication regarding student transitional thinking, especially in the current state of Common Core State Standards implementation, namely to help teachers understand learning progressions meaningfully.